Deceleration controlled brake system for vehicles



B. HELLER June 20, 19 50 DECELERATION CONTROLLED BRAKE SYSTEM FOR VEHICLES 3 Sheets-Sheet 1 Filed Aug. 8, 1947 B. HELLER June 20, 1950 DECELERATION CONTROLLED BRAKE SYSTEM FOR VEHICLES I Filed Aug. 8, 1947 3 Sheets-Sheet 2 June 20, 1950 B. HELLER 2,512,427

bECELERATION CONTROLLED BRAKE SYSTEM FOR VEHICLES Filed Aug. 8, 1947 3 Sheets-Sheet 5 I29 :5 ll. Illl Patented June 20, 1950 DEOELERATIDN CONTROLLED BRAKE SS DEM FOR WEH'IGLES Bedi'ich Heller, Prague, Czechoslovakia Application August 8, 194.7, Serial'No. 77.67.1516 Iii-Czechoslovakia March (13, .1946

"This -invention relates to "brake "systems for vehicles having 'a plurality of sets of independently operated brakes, for example to motor vehicles having front wheel andr'eariwhee'l brakes, and more particularly t'obrake systems -including inertia operated mechanism Torvaryingthe ratio .of the braking forces'fimposed upon the front wheel and the rear iwheelbrakesaccording tothe deceleration ofl'the Vehicle.

The wheels of a vehiclewillbecome'locked,and thus skiddin may result, whenthebrakingiforce (computed as effective at the circumference 'dfth'e jtire') 'isgrea'ter'than thej'frictionhetween a wheel tire and the road surface. Theffiction depends upon the'loadinjg o'f'the wheels, and this loading changes during travel ofthe vehicle, especially during brakelapplication'in the case of avehicle with two axles. The load .on'the ffront'twh'eel's increases during braking, and the load Tonthe rear wheels decreases correspondingly, whereby the'frictionlbe'tw'een' the rear wheelsand ,thero'ad is decreased, and only a part of the available brakinglpower can'b'e employed Withthe :conven- .tionzil braking systems having a fixed ratio of power transmission tothe ffront wheel brakes and'to the rear Wheelbrake's'.

It has beenoprqpose'chto obtain "a betterbraking effect byimposin'g an auxiliaryibr'akingforceupon the rear 'vvheels'this aux'iliary 'braking forcefbeing controlled "by "an .inerti'armass or rp'en'diilum movably supported on the vehicle. The proposed-arrangementvarie'd the -ratio of the effective brakin g forces applied to the front wheels "and rear wheels respectively, but "in an arbitrary -manner which did not prevent .a locking of the rear "wheels cnrapiddeceleration'produced byforceful braking or, alternatively, which avoid such wheel "lockin .by'limiting the auxiliary "braking 'fcrce to a low 'valueiwhich prevented 'fu'll use to? the available 'braking' power. "The auxiliary force was of a substantially 'fixed magnitude, being ;provided by 'ai-booster 'motor'upon a preseledtiefd displacement of the inertia mass, :and the total ibralrmg "forces applied 'toth'e rearwheels did-riot "vary'with the loading of therear'wheels; "Furthermore, theiauxiliary brake force 'was brought into operation by the inertia mass, without'actuation of the brake "lever, "when the vehicle travelled down hill, 'sothat'the vehi'cle was unintentionally "braked when the "road grade resulted in the preselecteddisplacement -o'f' the inertia mass.

The loading of the rear wheels does-decrease when traveling down a'slop'e, .and-someofthe prior proposals 'for 'varyin'gth'e *ratio of the braking fiorces at the front'a'nd'rear *wheels did not take ..cordance with changing distribution vof the loading of the front and rear wheels respectively,

.such changes in I load distribution arising from deceleration during braking, from travel on a sloping road .andflor from changes .in the location .and amount of the load Qcarried by the vehicle. An .object .is .to provide a brake system for a vehicle having apluralityof setso'f independently operable brakes upon which braking (forces vare imposed --.through actuation of a common brake lever, and in which the ratio of the braking 'forces at the .sets of ibrakes is automatically varied byan inertiamassin accordance with the 20 relative loadingseof-the vehicle wheels with which the setsof brakesare associated. More specifically, an object is to providea brake system of the character stated-in which the brake leverlefiects opposite sense according to slopeof the roadbed and the deceleration of the vehicle during brak- *ing. -0therobjects areztol-provide brake systems of the character-stated which include members adjustable imanually to vary the initial .-ratio of thelbrakingiorces applied tosets of independent- .1yop'erable-brakes and/or to vary the :ratio :of

power transmission in the same sense to the several :sets zcf :brakes according to :the mature or 1C01ldllii01'1r0f the-road travelled by the vehicle.

These and other objects, and the .advantages,

-:of the invention will .:be apparent from the ;following specification when takenwith the accomgpanying rdrawings in which:

:Fig. :is ta ifragmentarygplan view of -.a brake ssystemlembodying lthe invention as applied tog-a zmotor vehicleshaving azframe banexten'ding along thjong'itu'dinal axis'thereof; I V

Fig. 22 is a fragmentary side elevation of the same, with some lpartszshown in vertical :section'; Fig. 3 is a fragmentary-vertical section taken on the plane indicated by section line 3--="3 of Fig. "4 is a iragmentary "horizontal section through *thaboo'ster motor controlled *bythe inertia mass, as taken on the plane indicated by section lines 4-4 of Figs. 2 and 5;

Fig. 5 is a fragmentary vertical section taken on section line 55 of Fig. 4;

Fig. 6 is a fragmentary plan view of an alternative and adjustable connection between the booster motor and the force distributing member;

Fig. '7 is a fragmentary side elevation of another embodiment of the invention;

Fig. 8 is a fragmentary plan view of the same;

Fig. 9 is a front elevation as seen from the left side of Fig. 7;

Fig. 10 is a fragmentary vertical section taken on line Ifl-I I) of Fig. 7;

Figs. 11 and 12 are vertical sections taken on lines II-II and I2-I2, respectively, of Fig. 13

Figs. 13 and 14 are vertical sections on lines I3-I3 and I4I4, respectively, of Fig. 11;

Fig. 15 is a horizontal section as taken on the planes indicated by section line I5I5 of Fig.

Fig. '16 is a fragmentary vertical section taken on line I6-I6 of Fig. 15; and

.Fig. 17 is a fragmentary side elevation of another embodiment for use with mechanically operated brakes;

ated position determined by thecooperating stop projections 9 on the hub of lever 5 and the bearing block 4 respectively. The usual brake pedal I is secured to the brake lever 5, and a, spherical socket I I is carried by lever to receive the upper ball-shaped end of a rod I2 and support the same for rotation about its longitudinal axis and also for swinging movement in all directions.

The rod I2 is threaded into a sleeve I3 which terminates at its lower end in a fork in which a force distributing member or cross bar I4 is mounted on a pin or shaft I5 for rocking movement about an axis transverse to the longitudinal axis of rod I2.

The opposite ends of the cross bar I4 rest upon the longer arcuate arms IB and ll of bell-crank levers which are pivoted on a shaft I8 mounted in bearings I9 secured to support 2, the axis of the shaft I8 being spaced rearwardly from the rod l2 and the lever arms I6, I1 extending to opposite sides of the rod I2. The upper cylindrical end of the sleeve I3 is journalled in a bushing 20 in a, sleeve H which is connected by link 22 to the lower end of a lever 23 mounted on a shaft 24 supported on the bearing block 4.

Lever 23 may be rocked by a foot pedal 25 which is pivotally connected to the upper end of lever 23 and is urged counterclockwise by a leaf spring 26. Foot pedal 25 is latched in a desired position of adjustment by a pawl 21 connected to an arm of the foot pedal and cooperating with a notched segment 28 secured to the bearing block 4. The latch may be released by rocking the foot pedal 25 clockwise, and the foot pedal may then be moved forward or back to turn the lever 23 to displace the force distributing arm I4 substantially parallel to itself, thereby to vary in the same sense the effective lengths or power arms of the levers I6, I! of the mechanisms for imposing a braking force upon the respective sets of vehicle brakes. Maximum brake forces are obtained for any given displacement of the brake pedal Ill when the parts are adjusted as illustrated in Fig. 2 to provide a maximum spacing of the rod I2 from the axis of the levers l6, II. The brake forces may be reduced to lower magnitudes for travelon smooth asphalt or wet roads by depressing the foot pedal 25 to release the pawl 21 from the notched segment 28, and then pushing the foot pedal 25 forwardly, thus rocking the lever 23 to move the rod I2 closer to the axis of the levers l6, IT. The rod I2 is maintained in its new adjustment by releasing the foot pedal 25 to permit engagement of pawl 21 with a notch of the segment 28.

The force-distributing member I4 is turned with respect to the axis of the rod, by deceleration responsive means, to vary the ratio of the brake forces applied to the front wheel and rear wheel brakes. Mechanism for effecting this movement includes an arm 29 extending radially from the sleeve I3 and terminating in a ball end 30 seated in the cupped end of a rod 3|, see Fig. 1; the other end of rod 3I being threaded into a socket 32 which affords. a pivotal connection of the rod 3I to the ball end of a bell-crank lever 33 which is mounted on a bearing block 34 secured to the cross frame member 2. The other end of lever 33 is connected by a link 35 to the deceleration responsive mechanism which will be described later.

The turning of the force distributing member I4 with respect to the arcuate arms of bell-crank levers I6, I'I alters the ratio of the forces imposed uponthe two sets of brakes since the remaining portions of the independent force transmitting systems are illustrated as of identical construction. The connections of the arm I'Ia of lever IT to the hydraulic system of the brakes of the rear wheels are illustrated, in part in section, in Fig. 2, and some elements of the identical connections for the brakes of the front wheels are shown in dotted lines in Fig. l and identified by primed reference numerals. The forked end of a connecting rod 36 is pivoted to arm Ila of the lever I1, and the rearward ball end of the connecting rod is seated inthe socket of a piston 3! in the hydraulic pressure cylinder 38 of the rear brake system. A spring 39 is seated between the rear end of the cylinder 38 and a packing washer 40 at an inner end of the piston 31; the

spring urging the piston forwardly and thereby acting through connecting rod 36 to maintain the the .rear edge of the packing 40, and the rear end of the cylinder is connected'through a coupling nipple 46 and flexible tubing 41 to the brake cylinders (not shown) of the brakes 48. The

other pressure cylinder 38' is similarly connected by a nipple 46'-and tubin 41"to the brakes 48 on the frontwheels.

The deceleration responsive mechanism for automatically varying the ratio of the braking forces on the front and'rear wheelsincludes apendulum or inertia mass 49 pivoted on a bracket 50 to power cylinder 55 near the rear thereof.

assa led oscillate about an axis transverse to the vehicle, the bracket being secured toa cross member '51 of the vehicle frame. The -inertiamass 49 isconnected by a link 52 to an eye 53 on the end of the control rod 53 of the valve mechanism of a fluid pressure "booster motor, see Figs. 2, 4 "and 5, which comprises a housing '54- provided with a cylinder 55 which is closed tightly by a head 56. A piston slides in this cylinder and-has secured thereto a piston rod 58 which'is connected to the link 35 of the linkage system for adjusting the force distributing member 44 ang-ularly respect to the arcuate arms of levers 4'6, H of the mocha nisms for independentlytransmittingloralze forces to the front wheel brakes 4'8 and the rear wheel brakes 48. The piston 51 'is normallyretained in forward position by a helical spring 59, this position corresponding to equalit or to a low vratio of the braking forces applied to the rear wheels and front wheels of the vehicle. The piston rod 58 has rack teeth -60 meshing wi-tha'gear 6| which, in turn is mesh with the rack teeth 62 of the outer cylindrical sleeve 63 of the valve mechanism -for controlling the operation of the piston 5i. Sleeve 63 is slidable in a cylindrical bore of the housing 54, and a second sleeve 64 is slidable within the sleeve 63, the inner sleeve 454 having a central *bore in which the control rod 53 is supported for a limited range of sliding movement. The rod 53 has a radial flange 65 within the counter-bored rear end of the sleeve 64, and the rod is limited in its range of free movement by a bush'in-g 66 which is threaded'into the rear end of sleeve 64. The valve sleeve 64 is yielding-1y urged rearward-1y in the'outer valve sleeve '63 by a coiled spring 63a which is seated between the end of the sleeve -64 and skeleton frame 63b extending across the bore of the sleeve 6-3.

The outer valve sleeve -55 is provided with two annular grooves '61, '68 separated by a full-diameter portion 69 of the sleeve which has a close sliding fit within the valve cylinder, and a number of ports H1, H and 12 extend radially through the sleeve at the forward end of the rearward annular groove 67, at the rear end and at'the front end of the annular groove="6'8, respectively. The intermediate portion of the innervalve sleeve 64 has a circumferential groove T3 for cooperation with radial ports H1, 11 of the outer sleeve =63, and has radial ports 14 "opening into a chamber '15 at its forward end, the ports 54 aiming with ports 12 of the outer sleeve 63-when the valve mechanism is in normal inoperative position, as shownin Fig. 4. "Chamber '15 has an axial port 16 with a, flaring inner end for cooperation'with the conical tip -'of the :control rod 53 to form a valve.

A port ll opens through the housing 54 adjacent the forwardend of the groove 12, in the normal position of the "outer sleeve 65, and is con-- nected by anexterior passage "-18, see Figs. land 2, to a port it extending through the wall of the The interior of the cylinder "is thus in communication with the groove '12 and, in thenorma'l non-actua'ted condition of the "control mechanism, the groove 12 is open to atmosphere through ports 52 and I4, chamber 15, port -'l-6,'and a iilter-81l which extends across the forward end of the cylinder in which the outer valve sleeve 63 is loca-ted. The rear end of the cylinder is provided with "a flexible dust guard '81.

The-described booster motor is designed for operation -by' a motive-fluid under less than'atmospheric *pressure, but is to be understood that a'pressure fluid could introduced in front of the piston 51. The motive fluid connection 'to the booster housing 54 is through a nipple 8'2 set inthe wall of the valve cylinder in line 'withthe forwardend or the groove! of valve sleeve '63. A' t ibe 53 extends from the nipple 82 to the inlet manifold 84 of the internal combustion engine of -the vehicle.

The method of operation of the brake system is as "-fiollows: I

Assumingthat the several parts are initially in the-positions illustrated Figs. '1 and 2, equal forces will be imposed upon the levers 16, all :of the independent ilui'd pressure systems of the front wheel andir-ear wheel brakes. This equality of lonalre rorces -o'btains .since the force distributing barn is parallel to the :pivotal .axiso f the levers I 6 and i -l. The same fluid pressure .is established the pressure cylinders 38., 38' :and transmitted to the rear wheel brakes 48 and front wheel brakes 1:8 The pendulum inertia mass 49 swings inth'e direction of arrow Q :as the vehicle is slowed down iby the tor-airing, and acts through link- 5 2 to move the control rod 53 forwardly. The tiplof therodfil closes :the port 16 0f chamber 15 upon a preselected angular displacement of the inertiamass 49,- :and the inner valve sleeve =54 is moved forwardly upon any iurther displacements of the inertia mass. The closing .of the port .ZIl6-in:terruptS the communication between the motor cylinder .55 and atmosphere, .since the cylinder is continuously :open :to groove 6.! 0f the outer valve sleevefiB flout-groove 61 opens to :atmospine-re only' throughports :12, it-chamber 15 and port 16. booster motor is energized if the forward movement :of the inner valve sleeve .64 is sullicient to bring the groove 13 into line with therad ial ports H .0T "the outer sleeve 63. When thisoocurs, the igroovestl and 68 are :connected through "the groove 53 :and the ports 111., 12, and the inter iorof the motor cylinder .55 is in communication w ith the (engine manifold through the valveflmechanismland tube-85.. The reduction of air pressure in cylinder @5'5flllOVGS :the piston .55! rearwardlyzagainst the pressure of the spring 59, thereby "moving the piston. rod 58=to rock the bell-crank lever "id-clockwise. This results :in a thrust upon connecting rod .3! turns :the sleeve 43 counterclockwise and 'moves the force distributing member 14 to lengthen *the power arm of lever 1-6 or the brake .system for the iront wheels'and to 'shorten the power arm .of lever H of "the brake system for the rear wheels. The

ratioof the braking :forces of the sets of brakesis thus altered by the turning of the force .distributing member M, and the particular ratio whichis set up varies with the deceleration, i. .e. with thenngular di'splacement:of the inertia mass.

This proportional control is obtained through the rack and pinion connection of the outer valve sleeve fi's to the piston-rod 58. Thevalve sleeve 63 is moved forwardly when the reduced pressure within the cylinder =55 displaces the piston 51 and piston rod 58 rearwardly, and the motor stops when-the forward movement of the valve :sleeve 63 carries the ports H out et alinement with the groove 13 of the inner valve sleeve 64. The rate of deceleration may he such that the inertia mass 4'9 turns clock-wise a further amount after the booster motor stops, thereby moving control rod 58 and inner --v-alve sleeve 64 still further 'in a forwarddi-rection. The motor is thus energized since the groove 13 "is'again =al ined with ports H- oivalvesleeve-tt, andthepiston 154 moves rear-1' wardly until the corresponding, forward movement of the valve sleeve 63 moves the ports 'I.I out of communication with the groove 13 of valve sleeve 64.

The position of the force distributing member I4 with respect to the levers I6, I'I varies as a function of thedeceleration, and the braking forces applied at the rear wheels are therefore varied in accordance with the momentary load: ing ofthe rear wheels as that loading alters with the slowing down of the vehicle. By appropriate design of the mechanical and hydraulic transmission systems the braking forces at the rear wheels mayjbe kept below the values which would look the rear wheels, and the braking forces at the front wheels maybe correspondingly increased.

On a, decrease or removal of the force applied to the brake pedal l0, the brake lever 5 is moved clockwise towards its original position by the spring I and also by the springs in the hydraulic cylinders 38, 38; The braking action is decreased or removed entirely, and the inertia mass 49 turns counterclockwise towards its normal position, thus moving the control rod 53 rearwardly to open the port I6 of chamber in the inner sleeve 64. This re-establishes communication between the motor cylinder 55 and atmosphere, and the spring 59 moves piston 51 forwardly. This piston movement is accompanied by an equal rearward displacement of the outer valve sleeve 63, in view of the rack and pinion coupling, and also by an equal rearward movement of the inner valve sleeve 64 by the relatively weak coiled spring 63a. Forward movement of the piston is arrested if the port I5 of chamber 15 is'again closed by engagement with the tip of the control rod 53 before the vehicle comes to rest or is accelerated to restore the inertia mass 49 to, or beyond, its normal position corresponding to travel at constant speed. The position of the motor piston 51, and thereby the angular adjustment of the force distributing member I4, is thus directly and proportionally controlled by the deceleration-responsive inertia mass whether the rate of deceleration is increasing by a continued application of pressure on the brake pedal ID or is decreasing by a removal of .pressure from the brake pedal.

The friction between the rear wheels and the road also varies with the condition and nature of the road surface, the static load or weight on the rear wheels, and the slope of the road. The braking forces at both sets of brakes may be reduced by adjustment of the foot pedal to shift the force distributing member. [4 towards the pivotal axis of the levers I8, N. This adjustment may. be readily made by the operator when he encounters conditions of reduced traction, for example when the road surface is wet. The relative distribution of the static vehicle load between the front and rear wheels varies with the total load, and the initial ratio of the braking forces to be applied to the front wheels and rear wheels may be adjusted manually, and in accordance with the vehicle load, by turning the threaded rod 3| with respect to its socket end 32 to alter the effective length of the rod. Inspection of Fig. 2 will show that there is a relative movement of the vehicle frame and the inertia mass when the vehicle travels from a level road to an inclined road or hill, and that this relative movement is in the proper sense to compensate for. change in wheel loading which is due to the slope of the road; The load on the rear wheels decreases when travelling down a slope, but the vehicle-istilted counterclockwise from 7011 39081:

tion shown in Fig. 2 when the vehicle is on a downhill slope, andv this effects a relative displacement of the inertia mass in the direction of the arrow Q since the inertia mass hangs vertically below its pivot so long as the vehicle travels at a constant speed, This relative movement effects an initialoperation of the booster motor, in the case of-travel on mountain roads, which adjuststhe force distributing arm I4 to increase the effective length of lever arm I5 and to decrease the efiective length of the lever arm I! prior to the application of the brakes. Except in the. extreme case of a mountain road so steep as to effect the-initial adjustment of member I4 to the end position, as shown in dotted line in Fig. 1 the slowing down of the vehicle upon an application of the brakes will displace the inertia mass 49 to effect a further reduction in the braking forces applied to the rear wheels.

Another and more convenient adjustment for altering the initial ratio of braking forces according to the vehicle loading is shown in Fig. 6. The unitary bell-crank lever 33 shown in Fig. l is here replaced by a two-part construction comprising a lever 86 journalled on a shaft 8'! mounted in bearing block 34 and pivotally connected. to the socket end 32 of rod 3|, and a link orarcuate plate 38 also journalled on shaft 8'! and pivotally connected by link 35 to the piston rod 58 of the booster motor. The plate 88 is provided with a plurality of openings 89 for receiving a coupling pin, not shown, carried by a pring-pressed handle 90 mounted on the arm of thelever 86. The illustrated adjustment of the parts 85 and 88 is appropriate for a fully loaded vehicle, and the lever 86,96 may be turned clockwise, by lifting the handle to clear the pin from the end opening 89, and releasing the handle to engage the pin in another opening. This change in the linkage results in a counterclockwise adjustment of the force distributing member I4 to increase the initial braking force on the front brakes and to decrease the braking force on the rear brakes.

In the embodiment of the invention illustrated in Figs. '7 to 16 inclusive, a brake lever 9I is pivotally supported on a frame member 92 of the vehicle and connected by link 93 to an arm 94 fixed to the outer end of a shaft 95 which is journalled in the wall of a housing 96. A coiled spring 9? is connected between the lower end of the arm 9 and the housing 96 to restore the brake pedal to raised inoperative position upon a release of the brakes. A yoke or fork 98 is secured to the inner end of the shaft93 and has pins extending into the circumferential groove of a hub 99 fixed to a rod I00 which is supported in bearings I01, I02 for both sliding and turning movements. A force distributing member I03 is mounted on a pin or shaft I04 which extends transversely of the rod I00, and the opposite ends of the member I03 carry rollers I05 for engagement with the arcuate arms of bell-crank levers I06, I01 through which forces are transmitted to the brakes of the front wheels and the rear wheels, respectively. The force distributing lever is of shallow U-form, see Fig. 10, to locate the contact line of the rollers I05 and levers I03, I01 in a plane through the axis of the rod I00.

Pressure on brake lever 9| will rock the yoke 98 clockwise, thereby displacing the rod I00 forwardly, or to the left as viewed in Fig. 11, to rock the levers I06, I01 counterclockwise, see Fig. 15, about the axis of a shaft I08. which supports the 3 93., 313 19:. .Tbe eel ni m turn g,

*9 rod I=to vary the ratio of the=braking forcesat the front wheelsr and rear wheels includes a pinion I09 on. red: I 0.0 and; locked. againstrota.- tionwithc'respecttto rod I 00 by. amanually adijustable: coupling. Theepinionisjournalled. upon the. red I 00 but" held. against axial. movement, and the coupling. includes. a ratchetseg-ment I .I 0 fixed to the pinion I09 andia pawl III pivoted upon an arm 2v which. extends from the hub 99 of rod I00. The. pawl isnormally held in. engagementwithther'atchet II-0.by a coil spring H3; anditmay be released-by apin I.I4 slidably mounted in. a radial opening. in hub 9.9.. and. rod I00 and havingits-v inner. end. resting. ona. cam rod Ildjournalledwithin the, hollow forwardend of. the rod. I00". AL crankarm. H6 ispinned to the outer. endofithecam rod. and connected by I a. link- I I .I. toone. arm. of. a. lever. I18]. which. is pivoted uponan. arm IIB'secured totheendoi rod. I 00.. The arm I.I 0= extends vertically upward'fromthe. rod I 001 and terminates. inav handle [.2 0; which. entends..horiontally. and overlies the other-arm ofjthe lever. IIB. A lafispring I2.I is insertedbetween thelever. l.I B and the handleIZIl tourge. the lever II 8.. into thatpos'itionatf which the cam. rod. III doesnot force the pin LI ,4. out-.- wardly. t release the :pawl I M from. the. ratchet segment I'I0..

Thehandle I2'0.and. lever. I lilarelocated below an opening. I22. in. the. floor. boards- I23 of. the vehicleadjacent the. operatbrss'eat (-not. shown) where. they; are, conveniently available. for. man.- ual adjustment of the initial angular. arrange! ment of the rod. 7 I 00; and the force. distributing member I031 with respectto. the. levers I06. and I 01. of thebrake systems. This adjustment may be desirable whenthevehicle isunloadedor. when travelling. on..wet. roads.. The pawl. III is re.- leased fromthe ratchet. I .I 0by. graspingboth. the handle I: and-tthe. adjacent arm. of, lever- IIB'; thereby rocking lever I I8t0 force the arm. I.Ii.o cam-rod I I5; downwardly. and.turn. the. cam rod to force. the release: pin. H 11 outwardly..= The handle I20. can thenibe-tur-ned.clo ckwise,..see. Fig. 9, to-move the. rod. I 00 and ;force.-olistribut-ingi arm I03.clock-wise,. for example into the position indi-.- cated. by line .'A,A. of. Fig. 10,.to, lengthenthe power arm of lever I016Lof the front wheelbrakes and toshortenrthepowen arm of. lever. I0'Iof the rear. wheel. brakes. The. pinion.. I 00.. doesnotturn with i the rod. I 41.0 1 during. this. adjustment. since it. is. held stationary, by.- the decelerationeresponsive. mechanism... Uponrreleasingthe.handle I 20in its new positionthe. spring. I2 I.. turns lever I 5| BL to restore. themam; rod. .I.I alto. normal, position, and spring H31 draws thepawll I |,.|;.n'1tp.- engagement witlrtherack.I011.x

Theshorter. arms. oigthelevers I05; I0.I.termi.- natem rounded ends,I'065','.I-.0 whichebe'ar against pistons [21L slidable inpressurecylinders. I 2 5, I .20. respectively. The. cylinders. and atank I II. for. fluid; areformed asa housingwhichiis. bolted to the. housing. 96;. andthe .tank..portion. is 1- closed. by acover. plate. .IZILhaving; a; vented. .filling', opening; covered by, a..,can.. I231. The walls; of. the cylinders .h'aving' op'enings. I'3JOQfor. admittingg'fiuid. fromathetankf I 21' ;th'e.openings .beingmlearedlby, the. packing rings...i.3fl. of; pistonsi I241 when. the latter. are moved to. mar. inactive; end. positions 652'. helical; springs. I32. withinthe cylinders. I The closed endgof cylinder. I125. is. connectedlbytubing; I33 to the operating, cylinders. (not. shown),. of. brakes. I 34. on. thefrontwheels and ,cylinder I20 is=similarly connected-by tubing; I35 tQthebrakes liflbntherearwheel's.

The-pinion; I09 is in-mesh with aeraclc. I331 cut in-a piston rod..-I38.=which:is slidablee in bearing bosses. I3 9.. of the housing. 96 and! actuatedebyi a piston; M0 in:' at cylinder formed. the lower section? of; the housing 96.- The lower end of: the cylinder, is closed. by.- ahead. I 4| and: the, piston is; normally held: at its upper rangeuof. movement byy a. spring, ML located between. the; piston and thecylinder: head. The. operation-of the-motor cylinder: is. controlled by a. slide valve I43.sus-.- pended by a: link. I44 ifrom one. endiof a pair. of bars. forming. a. lever: I45. which is. pivoted. at about-.itscenter to.a link. I lfirand has its other endpivotally. connected to-the pistonrod.- 38;: The-upper. endlof link I 40. .is connected; to an arm I"; secured. to-ashaft I40 whichis journalled ina walloflthe housing 96. andhasapendiilum or. inertia mass I119- fixed to.-its outer end. A stophpin l ispreferablyset in. the wallof the housing; 9.5; to preventt a rearward; movement. of the pendulum during acceleration or whenrtravele linguphill.

The. valvev I43. slidesv vertically in the cylin: dricalpassage. I.5.I through. a.boss. I52 integral withthe housing; 96;. Ancentral. portion.-v I53 of valve. I43. iscircumferentially; grooved. to com necthorizontally alined, passages.- in certainpoe sitions 0f-the,Va1ve.. As. shownin Figs. l5and;16, the, passages. include. a. horizontal passage. I54 which opensintothe air cylinder. above the. piston I40, atransverse. hori'zontallpassage I 5.5.. which ex.- tendsv from passage; I 54-; andldiametrically across the cylindrical valve passage- IBJI atithedevelof the. groove I53 of valve. M3. when. the latter, is in. normal non-actuated;positionasshown. in Fig-.- 12, to terminate atithe. upper endloila. vertical passage I501, A. horizontal. passage. I55! connects the, lower. end of. passage. I5Bto.-the.air cylinder below the piston I40; A third.liorizontal-passage I58.extends diametrically across the .valvepassage I5I from the. vertical passage I56. to; a. hollow nipple I59 threaded into. the. boss.- I52 to provide a. connection forthe. tube; IBJI which. extends to. the manifold'or suction. spaceof anengine I Gil; see Figs. 8, and116.. J

, The method of; operation-isles follows:

Assuming. that the. rod. I00. and. pinion. are. so connected, through pawl. II 'I- and ratchet- I10; that the force distributing member-I03 is initially parallel. to the. axis. I08. of. the. levers I06" and I01; see. Fig 10, equal braking forces will beset upat the. front wheel brakes andithe. rear. wheel brakeswhen the brake. lever 9'! ispushedl dow'nv by the vehicle operator... vThe brake lever. rocks. the-shaft 95.and yoke. 98L.clockwise,. see. Figs; 11 and. 12,. thus. moving the. rod. I01). and; the force distributing member I03" to the left, and; the member. I03 rockslevers]. I06; I .0..'I' to press the pistons, I24; into.pressure-cylinders IZ5,".:I210 re, spectively. The pendulum. I49.- swings. t0th8. left; asthevehicle slows. down, .th'us, turning. shaft.) I 48iand arm. I41 clockwise, Fig. 12 and; arm I. presseslink.IA'6=downwardly.-to. rockthe lever. I45 counterclockwise. The lever MEL-moves thalihkl I44 and slide valve IE3 downwardly and; if.. the deceleration issuflicient, thegroove I53; of; valve I43. is horizontally. alined withthe. passage I58. see Fig. 16.. The.space.below. the. piston. I40. is connected to-the enginesuction. throughpassages I58, I56- and. I5.I',,andl the. reduced. air. pressure moves the. piston. I40. downwardly, inopposition to the. spring I.4Z.. The. piston. rod;v I 3 8 tunnsthe. pinion. I09 clockwise as it... moves downwardly, therebyturning. the nod. lflnlandforce. distributing,

. member. I103. clockwise... toincrease. the efiectiiic.

power arm of lever I06 which actuates the hydraulic brakes of the front wheels and to decrease the effect of power arm of lever I01 which actuates the hydraulic brakes of the rear wheels. Thedownward movement of piston rod I38 rocks the lever I45 clockwise, thereby lifting the slide valve to close the passage I58 and arrest the downward movement of the piston I40. The displacement of the piston I40, and the resultant angular arrangement of the force distributing arm I03 with respect to levers I06, I01, is determined by and varies with the angular displacement of the pendulum or inertia mass I49. If the brakes are applied more strongly after the piston I40 comes torest, the pendulum swings further to the left and forces the sliding valve I43 downward to open the, air cylinder to the engine suction. The piston I40 is moved downwardly again and by that amount which rocks the lever I45 to lift the valve I43 to close the passage I58.

When the pressure on the brake pedal is removed and th vehicle accelerated, the pendulum I49 swings back towards the right and lifts the link I46 and, through the lever I45, the slide valve I43. The groove I5 3 of the valve alines with the passage I when returned to normal position, and the air spaces above and below the piston I40 are then in communication through the passages I54, I55, I56 and I51. The spring I42 returns the piston to its upper position, and piston rod I38 turns pinion I09 during this travel of piston I40 to return the rod I00 and force distributing member I03 to, their initial positions. The return of the several parts of the apparatus will take place in several steps or stages when the pendulum I49 moves slowly back to its normal position after an initial and strong application of the brakes.

An adaptation ofthe app aratus of Figs. '7 to 16 for use with mechanical brakes is illustrated in Fig. 17. The apparatus within the housing 96v is the same as that previously described except that the force distributing lever I03 is at the left of the levers I06a, I0'Ia, and the brake pedal 9Ia is keyed directly to the shaft 95. The lever I06a is rigidly fixed to the hub of a lever I62 which is at the outside of housing 96 and connected to the keys of the front wheelbrakes by a rod I63. Similarly, the lever I0'Ia is rigid ly secured to the hub of a lever I64 which is connected through rod I65 to the keys of the rear wheel brakes. The distribution of the braking forces between the sets of wheels is controlled by the angularposition of the pendulum I49 in exactly the, same manner as described above with reference to Figs; '7 to 16.

It is to be understood that the invention is not limited to the particular constructions herein described and illustrated since various changes may be made in the parts and in their relative sizes, shapes and relationships without departure from the spirit and scope of the invention as set forth in the following claims.

Iclaim: j

1'. A brake system for vehicles comprising two sets of independently operable brakes, a brake lever, a rod, means connecting said rod to said thereof, a force distributing member pivotally connected to said rod for rocking movement about an axis transverse to said longitudinal,

axis, a pair of levers pivoted'for rocking about an axis atone side of said rod and extending from said rocking axis symmetrically to op positesides of said rod for engagement by the opposite ends of said force distributing member, whereby turning of said rod about its longitudinal axis displaces the opposite ends of said force transmitting member in opposite sense with respect to the rocking axis of said levers, force transmitting means connected to the respective levers for individually actuating said sets of brakes, and deceleration-responsive means for turning said rod with respect to its longitudinal axis, thereby to vary the ratio of the forcesim posed upon said force transmitting means by said brake lever and force distributing member.

2. A brake system as recited in claim 1, wherein said deceleration-responsive means includes aninertia mass movably. supported on the vehicle for displacement as a function of the vehicle deceleration, motion transmitting means for adjusting said rod about its longitudinal axis to vary the ratio of saidtransmitted forces, a power source for actuating said motion trans mitting means, and means controlled bydisplacement of said inertia mass to energize said power source to actuate said motion transmitting means in proportion to the inertia mass displacement.

3. A brake systemas recited in claim 2, where-- in said motion transmitting means comprises a linkage including levers adjustably connected to vary the initial angular adjustment of said red at the normal non-displaced position of said inertiamass.

. 4. A brake system as recited in claim 1, wherein said means connecting said rod to said brake lever includes members manually adjustable to turn said rod to set said force distributing member in a preselected position with respect to the rocking axis of said levers in the normal nondisplaced position of said deceleration-responsive means.

5. A brake system as recited in claim 1, in combination with manually adjustable means to displace said force distributing member substantially parallel to itself and toward or away from the rocking axis of said levers, thereby to alter the effective power arms of both levers of said pair in the same sense.

6. In a brake system for a wheeled vehicle, the combination of a brake lever, a rod pivotally supported by said lever for universal motion, a sleeve secured to said rod, means supporting said sleeve for turning about the axis of said rod, a force distributing member pivoted upon said sleeve for rocking movement about an axis transverse to the'axis of' the rod, a pair of bell-crank levers having arcuate arms positioned at opposite sides of the rod axis for engagement by the opposite ends of said force distributing member, front wheel and rear wheel brakes, independent transmission systems connecting one bell-crank lever to the front wheel brakes and the other bellcrank lever to the rear wheel brakes, an inertia mass supported for rocking movement about a horizontal axis transverse to the longitudinal axis of the vehicle, and power means energized by said inertia mass to turn said rod and force distributing member with respect to said bell-crank levers to vary the ratio of the braking forces transmitted to said front wheel brakes and rear wheel brakes in accordance with the relative loadings of the front wheels and the rear wheels.

'7. In a brake system for a wheeled vehicle, the invention as recited in claim 6 wherein said power means comprises a fluid pressure motor of the cylinder and piston type, a source of motive fluid, valve means responsive to relative displacements of said inertia mass to connect said motor to said motive fluid source, and means responsive to displacement of the piston of said motor to actuate said valve means to break the connection of said motor to said motive fluid source upon completion of, a piston displacement proportional to the inertia mass displacement.

8. In a brake system for a wheeled vehicle, the invention as recited in claim 7, wherein said valve means comprises an inner and an outer sliding valve sleeve, a control rod actuated by said inertia mass for moving the inner valve sleeve to connect the fluid pressure motor, and said outer valve sleeve is connected to said motor piston for actuation thereby to constitute said means for breaking the connection of said motor to said motive fluid source.

9. In a brake system for a wheeled vehicle, a

brake lever, a rod, a pair of bearings supporting said rod for axial displacement and for turning, a force distributing member pivoted upon said rod for rocking movement about an axis transverse to the axis of said rod, a pair of bell-crank levers having arcuate arms positioned at opposite sides of the rod axis for engagement by the opposite ends of said force distributing member, front wheel and rear wheel brakes, independent transmission systems connecting one bell-crank lever to the front wheel brakes and the other bell-crank lever to the rear wheel brakes, an inertia mass supported for rocking movement about a horizontal axis transverse to the longitudinal axis of the vehicle, and power means energized by said inertia mass to turn said rod and force distributing member with respect to said bell-crank levers to vary the ratio of the braking forces transmitted to said front wheel brakes and rear wheel brakes in accordance with the relative loadings of the front wheels and the rear wheels.

10. In a brake system for a wheeled vehicle, the invention as recited in claim 9 wherein said power means comprises a fluid pressure motor of I the cylinder and piston type, a source of motive fluid, valve means responsive to relative displacements of said inertia mass to connect said motor to said motive fluid source, and means responsive to displacement of the piston of said motor to actuate said valve means to break the connection of said motor to said motive fluid source upon completion of a piston displacement proportional to the inertia mass displacement.

11. In a brake system for a wheeled vehicle, the invention as recited in claim 10, wherein said valve means comprises a sliding valve connected by a link to one end of a lever, the other end of the lever being pivotally supported on the motor piston rod, a link pivotally connected to an intermediate point of said lever, and a crank arm actuated by said inertia mass pivotally connected to the other end of said link.

12. In a brake system for a wheeled vehicle, the invention as recited in claim 9, wherein said power means includes a pinion supported for rotation on said rod and in mesh with a rack on the piston rod of said power means, in combination with means for securing said pinion against rotation with respect to said rod.

13. In a brake system for a wheeled vehicle, the invention as recited in claim 12, wherein said securing means includes means adjustable to vary the relative angular relation of said pinion and said rod, thereby to adjust the initial angular position of said force distributing member with respect to said bell-crank levers.

' BEDRICH HELLER.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 1,795,145 Rouanet Mar. 3, 1931 1,874,822 Smith Aug. 30, 1932 2,073,163 Martin Mar. 9, 1937 2,074,718 Bohannan Mar. 23, 1937 2,115,071 Hunt Apr. 26, 1938 2,183,283 Sampietro Dec. 12, 1939 

